Math has never been a strong suit of WTBTS.
See the Question From Readers on page 30:
"How long did this inspection and cleansing
work take? It extended from 1914 to the early part
of 1919. This period of time includes both the
1,260 days (42 months) and the symbolic three
and a half days referred to in Revelation chapter
11."
And the accompanying chart:
Go here and try for yourself:
http://www.timeanddate.com/date/dateadd.html
Or, if you don't want to:
"from 1914" is when? Presumably, October, since that's when they say the Kingdom was born.
Starting with October 1, 1914, adding 1260 days brings us to March 14, 1918.
They view the 42 months (1260 days) as one time period, then another 3 1/2 days (this is symbolic, of course...)
From that, they get to 1914.
In order to do that, the 3 1/2 days would not follow the day for a year principle, otherwise, it would be ANOTHER 1,260 days, by the statement in the paragraph above and the chart on that page, which would bring us to August 25, 1921. But, they are not viewing this second 3 1/2 days as 3 1/2 years. Just what are they viewing it as? Who knows. It's "symbolic". If the 1,260 days is literal, then the 3 1/2 days should be literal, too, right? Oh, wait... WTBTS mixes up literal and symbolic/figurative whenever it suits them. But, let's say they are literal. This would make the full period of the 1,260 days plus 3 1/2 days equal to 1263.5 days which brings us to sometime on March 17, 1918.
There is NO WAY to get from 1914 to 1919 using the math in Revelation 11.
Am I wrong? Is my math off?